1. Field of the Invention
The present invention relates generally to vacuum cleaners, and more particularly, to improvements in grille members and cyclone dust-collecting apparatus for vacuum cleaners.
2. Description of the Related Art
In general, a cyclone dust-collecting apparatus is used in a vacuum cleaner designed to operate without a dust bag, to draw in dirt-laden air, generate a rotating current in the dirt-laden air, and separate dirt from the air using centrifugal force generated by the rotating current.
FIG. 1 is a view schematically illustrating a conventional cyclone dust-collecting apparatus applied to a vacuum cleaner.
As shown in FIG. 1, the cyclone dust-collecting apparatus 1 comprises a cyclone separator or cyclone body 10, a suction part 11 for drawing in air therethrough, a discharge part 12 for discharging dirt-removed air therethrough, a grille member 13 connected to the discharge part 12, a dirt receptacle 14 for collecting and storing dirt therein, and a flange 17 for preventing the dirt stored in the dirt receptacle 14 from being dispersed or scattered up by air currents.
Operation of the cyclone dust-collecting apparatus 1 is as follows.
Dirt-laden air is drawn in from a cleaning surface by a vacuum motor (not shown) of the vacuum cleaner and guided into the cyclone body 10 through the suction part 11.
Since the suction part 11 is connected tangentially to an inner circumference of the cyclone body 10, the air guided into the cyclone body 10 rotates along the inner circumference of the cyclone body 10 in a direction of arrow A shown in FIG. 2 so that dirt is centrifugally separated from the air.
The dirt centrifugally separated from the air by the rotating current is guided by the inner circumference of the cyclone body 10. Air currents and gravity cause the dirt to fall down into and to be stored in the dirt receptacle 14 via a communication space 15 disposed between the cyclone body 10 and the flange 17.
When the dirt stored in the dirt receptacle 14 is forced upward by an abnormal air current, an under surface of the flange 17 guides the dirt downward, so that the dirt is collected again into the dirt receptacle 14.
The air having the dirt removed therefrom is filtered through air passages 16 of the grille member 13 connected to the discharge part 12 and discharged from the cyclone dust-collecting apparatus I through the discharge part 12.
In the cyclone dust-collecting apparatus 1 constructed as above, as shown in FIG. 3, the grille member 13 consists of a cylindrical body having a plurality of air passages 16, each of which is formed in the shape of a hole or slot. The respective air passages 16 are provided with a leading surface 25 and a tail surface 24. The leading surface 25 and the tail surface 24 are disposed vertically relative to the direction (shown by arrow A) of the rotating air current to draw in the air after the dirt is centrifugally separated by the rotation of the air.
Accordingly, when the air rotates to form the rotating current in the direction of arrow A and thereby to centrifugally separate the dirt therefrom, the air at the vicinity of front ends 24a of the tail surfaces 24 may be stagnant, since the leading surface 25 and the tail surface 24 of the air passages 16 are disposed vertically to the proceeding direction of the rotating current. These areas of stagnant air may cause the dirt, especially fine dust, contained in the air to gather and be accumulated in the vicinity of the front ends 24a of the tail surfaces 24 while the vacuum motor operates. The accumulated fine dust then remains in the vicinity of the front ends 24a of the tail surfaces 24 when the vacuum motor is stopped, with the result that this dust is discharged out of the dust-collecting apparatus 1 with the initial air flow when the vacuum motor is started again. The fine dust discharged out of the dust-collecting apparatus 1 may clog a dust filter (not shown) installed prior to the vacuum motor, thereby reducing dust-collection performance of the vacuum cleaner.